Lecture #2 Flashcards by Kristy Lincoln

What is an atom?

Smallest unit of matter which can partake in a chemical reaction

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What is formed when two or more atoms are joined together?

A molecule

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Does a molecule have to be composed of all different atoms?

No, it can contain same molecules eg. O2

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What 3 things does is every atom composed of?

Nucleus, Proton, Neutron

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Protons and neutrons are equal when…?

The atom is stable

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The atomic number is the number of…?

Protons

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The nucleus will always carry a net positive charge because?

Neutrons have no charge so there is just positive charge in the nucleus

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Electrons are located in….?

Orbitals outside of the nucleus

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Why are nuclear contents referred to as stable?

Because they do not participate in chemical reactions

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When an atom loses an electron, it has what type of charge?

Net positive

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When an atom has an overall negative or positive charged, it is referred to as an?

Ion

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Atoms carrying a negative charged is called? Positive?

Anion, Cation

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A chemical bond is formed when

The outer shell electrons interact

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What are the 3 types of chemical bonds found in living organisms?

Covalent
Ionic
Hydrogen

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Are covalent bonds strong or weak?

Very strong

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How are covent bonds formed?

When two atoms share electrons with their outer shell

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What type of bond does water have? Between what elements?

Covalent bond between hydrogen and oxygen

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How are ionic bonds formed?

As a result of the attractive force between ions of opposite force, they do not share electrons, rather donate

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Are hydrogen bonds weak or strong?

Weaker than covalent

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What element is most common in human cells? Why?

Carbon, because it has sides that can covalent bond

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How is a hydrogen bond formed?

When hydrogen is covalently bonded to oxygen or another electron loving molecule

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What are polar molecules?

Unequal sharing of electrons

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What type of sharing occurs in hydrogen bonds? Why?

Polar molecules result because the atom bound to hydrogen is electron loving, it holds it closer to the nucleus then hydrogen resulting in unequal sharing

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Explain which atom receives partial negative/positive charge on polar molecules

Partial positive for hydrogen

Partial negative on the electron loving atom

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Are hydrogen bonds strong or weak?

Weakest out of the 3

What are organic compounds?

Compounds containing carbon

What are inorganic compounds?

Compounds that do not contain carbon

What type of compounds do organisms require to live and reproduce?

Inorganic

What allows water to be so able to dissolve many things?

The partial positive and negative bonds allow it to dissolve many things

What molecule is called a partial solvent? What does that mean?

H2O because it dissolved material and electron are not equally shared

How many hydrogen bonds can H2O have max?

What are 4 reasons why living things make such good use of water?

1. Water is an excellent solvent 2. Every H2O molecule can form hydrogen bonds with other water molecules 3. Water is a great temperature buffer because of its strong hydrogen bonds 4. Water is easily split into its component ions H+ and OH-

Why is water a great solvent?

Because water can dissolve many ionic compounds

A solution with water is formed when?

The partial positive region within H2O molecules surround ions and partial negative region of H2O molecules surround positive ions, holding them in a solution

What gives water such a high boiling point?

Because hydrogen is able to have 4 bonds allowing it to form networks of interconnected molecules

What allows water to stay liquid in most places it is found on earth?

It's high boiling point

Why is water such a great temperature buffer?

Because of its strong hydrogen bonds

What allows water to play key roles in many chemical reactions?

Its ability to be easily split into its component ions H+ and OH-

What outer 4 electrons allow it to form what?

4 covalent bonds with lots of different atoms

What are the 4 major classes of organic compounds found in living things?

1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

What is the energy source that can immediately used by cells?

Carbs

Are carbohydrates polar or non polar?

Polar (so they dissolve in water)

What elements do carbohydrates always have?

C, H and O

What ratio is carbohydrates usually found in

C, H2, O

What are the 3 major groups of carbs?

1. Monosaccharide 2. Disaccharide 3. Polysaccharide

What are two examples of monosaccharides?

Glucose and Fructose

What does monosaccharide mean?

One sugar

What is an example of a disaccharide? What is it made up of?

Sucrose, made from glucose and fructose

What does disaccharide mean

Two sugars

What does 'Like Dissolved Like' mean?

ex. H2O is polar as well as sugar therefore it dissolves well

What is a polysaccharide made up of?

Many sugars (hundreds)

Which type of carb is often no water soluble? Why?

Polysaccharides because they are often too large

What are 3 examples of polysaccharides?

Starch, Cellulose and Glycogen

What type of polysaccharide allows us to store excess sugar?

Glycogen

What are 3 types of lipids?

1. Fats 2. Complex lipids (phospholipids) 3. Steroids

Why are lipids heterogenous?

Because many things represent it

Where are lipids found in a cell?

Cell membrane, phospholipid bilayer

Why are lipids used as a means of energy storage?

Because a gram of fat can store 2x the mount of energy compared to a sugar

What does are body store extra energy as

Lipids

Why are lipids non reactive to water?

Because they are non polar

What are fats composed of?

A glycerol molecule and 1-3 fatty acids?

What are 3 types of fats? What are they composed of?

Monoacylglyceride- Glycerol and 1 Fatty Acid Diacylglyceride- Glycerol and 2 Fatty Acids Triacylglyceride- Glycerol and 3 Fatty Acids

Fatty acids can be different by whether it is.......?

Saturated or Unsaturated

What is the difference between saturated and unsaturated fats

Saturated= No double bonds, and saturated with a hydrogen atom Non saturated= Has at least 1 double bond, fewer hydrogen atoms (less saturated with hydrogen)

What are complex lipids made up of?

Glycerol, 2 Fatty Acids and a phosphate group

What makes steroids structurally distinct from other lipids

It's 4 ring structure

Steroids are found in mainly?

Eukaryotes not prokaryotes

What are two examples of steroids

Cholesterol and Vitamin D

Proteins are formed from

Amino acids

How many known amino acids are there?

What are all proteins (amino acids) composed of

Carbon, Oxygen, Hydrogen and Nitrogen

Each amino acid has what 3 molecule compounds?

Amino group, Carboxyl group and a side group (which is different on each AA)

What determines the chemical properties of the amino acid?

The side group R-

What type of bond holds the amino acids together when forming a protein? Are they ionic, covalent or hydrogen bonds)

Peptide bond which are covalent (can be other)

What are short chains of AA called? Long chains?

Peptides, Polypeptide which are proteins

What determines the shape of the protein?

The specific amino acid sequence

What two things are proteins important for in a cell

1. Structural components (membrane channels) | 2. Enzymes which increase the rate at which chemical reactions occur in the cell

What are nucleic acids made up of?

Nucleotides

What are the 3 components are nucleotides are made up of?

Nitrogenous base, Pentose sugar and a phosphate group

What are two nitrogenous base 'groups'

1. purines | 2. pyrimidines

Which nitrogenous base contains two rings. Which contains one?

2 rings- purines | 1 ring- pyrimidines

What are two types of purines?

Adenine and Guanine

What are 3 types of pyrimidines?

Cytosine, Thymine and Uracil

What is a pentose sugar?

A 5 carbon sugar

What are two types of pentose sugars?

Ribose and Deoxyribose

What is the phosphate group in a nucleotide attached to and what does it serve as?

Attached to the nucleotide and serves as a site for attachment for the next nucleotide

What are two types of nucleic acids

1. Deoxyribonucleic acid (DNA) | 2. Ribonucleic acid (RNA)

What is the difference between DNA and RNA

DNA- composed of Deoxyribose sugar | RNA- composed of Ribose sugar

Which Nucleic acid is single stranded, which is double?

DNA- double | RNA- single

How is each strand of DNA held together?

A hydrogen bond

What in DNA forms the genetic instructions for the organism

The oder of nucleotide sequence which is very specific

Which nucleotides make up DNA vs RNA

DNA- A,C,T,G | RNA- A, C, U and G

What does RNA do?

Communicates instructions when forming DNA